I get where you're coming from, but I (and my wife) look at it from the other side.

Not that we're dead, but from the side of "growing" rather than "aging." Most people at some point stop growing mentally/emotionally/spiritually/physically (I don't mean getting taller).

There are the classic high school jocks who peak in High School (refer to Bruce Springsteen's song, "Glory Days) and never move on. There are people who never leave the "hard-partying" phase of their 20s...until they have a heart attack at age 45.

The most prevalent (IMO) "end of development"-types are those like in your article. People who never question their own beliefs and thus never move on from where they started. This is (again IMO) because, as you say, partly because they never physically moved away from where they were born and raised.

Both my wife and I are immigrants and happy with where we're living, so we're biased. That being said, we both work hard to continue our mental, emotional, and physical development as our lives and our bodies change over time.

That development is not dependent on us having emigrated, but maybe we have the personalities that lead us to want to emigrate (or at least move away), which is the same kind of personality that wants to continue to grow as long as we are vertical.